Series parallel transformer connection



Feb. 7, 1933. F. w. GAY 1,896,397

SERIES PARALLEL TRANSFORMER CONNECTION Filed May 28, 1930 2 Shets-Sheet 1 FIG.I.

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H00 L\ x no 2200 U L g 220 m 1 S 8 a 8 N N N Al INVENTOR Feb. 7, 1933. v F. w. GAY 1,896,397

SERIES PARALLEL TRANSFORMER CONNECTION Filed May-28, 1930 2 Sheets-Sheet 2 FIG. 9.

INVENTOR Patented Feb. 7, 1933 FRAZER W. GAY, OF NEWARK, NEW JERSEY SERIES PARALLEL TRANSFORMER CONNECTION Application filed May 28,

r This invention relates to the switching of transformer windings from series to parallel connection when the number of windings connected in series is even. The advantages to be obtained by the series parallel arrangement are fully explained in my Patent No. 1,7 98,87 4.

It is an object of this invention to equip a transformer with an even number of circuits per winding, adapted to be switched into either series or multiple connection as desired. It is a further object of this invention to arrange the magnetic circuits for maximum efficiency at light loads so that when the transformer is operated with windings in multiple connection, there are in effect two separate transformers, each having its own separate magnetic circuit, whereas when the windings are connected in series there is in efiect a single transformer having one short magnetic circuit common to its windings.

It is a further object of this invention to arrange the magnetic circuits for maximum efiiciency at heavy loads so that when the windings are connected in multiple there is in effect a single transformer having one magnetic circuit common to its windings.

It is a further object of this invention to shunt the load out of the series windings, except one in each circuit, after which a second switching operation places the shunted windings in multiple with the windings left in circuit.

It is a further object of this invention to provide a double throw switch at one end of each series group whereby the polarity of the windings at that end may be reversed.

It is a further object of this invention to provide this arrangement in order to obtain a relatively high efficiency at light loads and a relativelyhigh transformer capacity at heavy loads. This object is accomplished by permanently connecting all the windings in each the load reaches apredetermined value a switch in eachphase circuit is closed to shunt the load out of all the windings in this phase circuit except one. The next switching oper 1930. Serial No. 456,753.

ation places the shunted windings in multiple with the working windings.

It is a further object of this invention to place one half of the windings on one magnetic circuit and one half of the windings on another magnetic circuit, so that the windings on one magnetic circuit may have a voltage impressed on, or induced in them, independently of the voltage impressed on or induced in the windings on the other magnetic circuit.

1t is a further object of this invention to switch windings from series to multiple connection without interfering with the ability of the transformer to continuously carry load.

Other objects and advantages will become apparent from the specification, taken in connection with the accompanying drawings wherein the invention is embodied in concrete form.

In the drawings:

Fig. 1 is a cross section of the core and coils of one form of transformer of this invention.

Fig. 2 is a diagrammatic representation of the windings of Fig. 1 including switches for use with said windings.

Figs. 3, 4, and 5 represent voltage vectors respectively with two windings operating in series in primary and secondary, one winding carrying load in primary and secondary and two windings operating in multiple in primary and secondary to carry load.

Fig. 6 is a diagrammatic representation of a transformer of the present invention having four windings in its primary and four windings in its secondary adapted to be connected in series or multiple relation.

Figs. 7, 8, and 9 represent respectively the transformer windings of the low tension when connected with all windings operating in series connection, with only one winding operating under load and with all windings operating in multiple relation under load.

In Fig. 1 a transformer 1 has low tension windings L1 and L2 inclosing magnetic cores 2 and 3 respectively. Cores 2 and 3 are joined by magnetic yokes 6 and 7 and these yokes are shunted by magnetic legs 4: and 5. Low tension coils L1 and L2 are inclosed by high tension coils H1 and H2 respectively.

Fig. 2 shows high tension windings H1 and H2 of Fig. 1 permanently connected by lead 14 and low tension coils L1 and L2 permanently connected in series by lead 15. A double pole double throw switch 21 has the hinge clip of one pole connected to winding H2 by lead 24 and the hinge clip of the other pole connected to winding L2 by lead 27. The jaws cooperating with the switch pole connected to the high tension winding are connected one to each of the high tension busses 8 and 9 while the jaws cooperating with the switch pole connected to the low tension winding are connected one to each of the low tension busses 11 and 10 as shown.

A double pole single throw switch 16 has the hinge clip of one pole connected by wire 18 to lead 15 and the hinge clip of the other pole connected by wire 19 to lead 14. The respective jaw clips are connected by wire 17 to bus 10 and by wire 20 to bus 9.

If now the ratio of turns of windings H1 and L1 is ten to one and of windings H2 and L2 is ten to one and the ratio of the voltages of the high tension busses 8 and 9 and the low tension busses 10 and 11 is ten to one and the voltages are 2200 and 220 respectively, then Fig. 3 will represent the vector relation of the low tension voltages in L1 and L2 when switch 21 is thrown'down and switch 16 is open, so that the low tension windings L1 and L2 are in series and the high tension windings H1 and H2 are also in series. Obviously the voltages of H1 and H2 will be substantially ten times the voltages of L1 and L2.

Fig. 4 shows the voltage on L1 to be 220 volts immediately after the closing of switch 16. v The voltage of L2 will be zero i. e. it will be short circuited by switches 16 and 21 and low tension bus 10. It will have only a slight tendency to carry current, since core 2, Fig.1 is shunted by core legs 4 and 5 and legs 4 and 5 will carry substantially all the magnetism of leg 2 and leg 3 will carry substantially none.

'Fig. 6 shows diagrammatically a transformer having a magnetic core 54 with encirclin windings L1 and H1 and L3 and H3 and also having a magnetic core 55 with encircling windings L2 and H2 and L4 and H4. Windings H1, H2, H3, H4 are con nected in series by leads 64, 65, and 67 and windings L1, L2, L3, L4 are connected in series by leads 63, 66, 68. A switch 58 is connected in a manner similar to switch 16 in Fi 2. A six pole switch 7 0 has its hinge clips 3, 74, 75 connected respectively to the junctions of windings H2 and H3 and H3 and H4 and to the terminal end of H4. Switch has its hinge clips 76, 77 and 78 connected respectively to the junctions of It will thus be seen that with switch 70 thrown down and switch 58 open, the windings H1, H2, H3, and H4 will be connected in series across busses 50 and 51 and the windings L1, L2, L3, and L4 will be connected in series across busses 52 and 53.

It now switch 58 is closed, winding H1 will be connected directly across high voltage busses 50 and 51 and winding L1 will be connected directly across low voltage busses 52 and 53.

The upper jaw clips of poles 73, 74, of switch 7 O are connected respectively by wires 82, 83, and 84 to busses 50, 51, and 50 and the upper jaw clips of poles 76, 77, and 78 of switch 70 are connected respectively by wires 86, 85, and 86 to busses 53, 52, and 53. If switch 58 is closed and switch 70 is thrown up, then windings H1, H2, H3, and H4 will be connected in multiple across busses 50 and;

51 and windings L1, L2, L3, and L4 will be connected in multiple across busses 52 and 53 and the transformer will have substantially four times the capacity that it will have with switch 7 O thrown down and switch;

58 open i. e. with windings H1, H2, H3, and H4 in series and windings L1, L2, L3, and L4 in series.

Fig. 7 shows that the voltage in each low tension winding will be substantially 55 when these windings are connected in series across busses 52 and 53 and when the voltage on busses 52 and 53 is 220. lVith turn ratio Hl/Ll, H2/L2, H3/L3, and H4/L4 each equal to ten, then the voltages across H1,

H2, H3, and H4 will be substantially 550 each.

Fig. 8 shows that if switch 58 is now closed the voltage across L1 will be 220 and since L1 and L3 are on the same core and have the same number of turns the voltage across L3 will also be 220. Coils L2 and L4 are on a common magnetic circuit, inde pendent magnetically of the magnetic core common to L1 and L3. Now coils L2, L3, L4 are short circuited through bus 52 and since-L3 has induced in it 220 .volts, coils L2 and L4 will build up a total voltage equal to 220 i. e. the voltage across L2 will equal the voltage across L4 (since they are on a common core and haveequal turns) and will be one half that across L3.

If now switch 70 be thrown up the load will be carried by H1 and L1 while switch 70 is opened and when switch 70 is closed in the up position all the high tension windings will be in multiple across busses 50 and 51 and all the low voltage windings will be in multiple across busses 52 and 53 and the windings will have voltages across them as shown in Fig. 9.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is 1. In a transformer having a plurality of primary windings connected in series and a plurality of secondary windings, each of said primary windings being arranged in inductive relation to an individual secondary winding, said secondary windings being connected in series, switch means to throw the load on to one primary and its inductively related secondary winding and .additional switch means to reverse the polarity of one half of said windings and connect all said primary windings in multiple and all said secondary windings in multiple.

2. In a transformer having windings adapted to be switched from series to multiple relation or vice versa, switch means to maintain the load through certain windings while certain other windings are being switched and additional switch means to switch said certain other windings into multiple relation with said certain windings.

3. In a transformer, a plurality of primary coils connected in series and a plurality of secondary coils connected in series, each of said secondary coils being inductively related to a respective one of said primary coils, core means providing two winding legs, one-half of said primary coils together with one-half of said secondary coils being mounted on one of said winding legs and the other half of said primary coils together with the other half of said secondary coils being mounted on the other of said winding legs, and switching means for connecting said primary windings in multiple and for connecting said secondary windings in multiple.

4. In a transformer, windings adapted to be switched from series to multiple relation or vice versa, switching means for effecting such switching operations, core means providing a short magnetic circuit interlinking all of said windings and arranged to carry substantially all the magnetic flux for one of said connections, said core means providing leakage paths cooperating with parts of said short magnetic circuit and arranged to establish two connected magnetic circuits for said second connection.

5. In a transformer, windings adapted to be switched from series to multiple connection or vice versa, means for effecting said switching operations, a core providing a relatively short magnetic circuit interlinking all of said windings, said short magnetic circuit being arranged to carry substantially all the transformer flux during said series connection, said core providing leakage paths arranged to substantially by-pass a portion of said short magnetic circuit during said multiple connection.

6. In a transformer, windings adapted to be switched from series to multiple connection or vice versa, means for effecting said switching operations, a core providing a short magnetic circuit interlinking all of said windings and arranged to carry substantially all of the transformer flux during operation with said series connection, said core providing leakage paths connected to said short magnetic circuit, said leakage paths carrying only a little flux during said series operation but acting to carry large amounts of magnetic flux during operation with said multiple relation.

7. In a transformer, windings adapted to be switched from series to multiple connection or vice versa, means for effecting said switching operations, a core providing two magnetic circuits, one-half of said windings being mounted on one magnetic circuit and the other half of said windings being mounted on the other magnetic circuit, parts of said two magnetic circuits cooperating in forming one short magnetic circuit during periods of operation using said series connection.

8. In a transformer, a core providing two magnetic circuits, two groups of windings, each of said groups of windings interlinking a respective one of said magnetic circuits, means for connecting said windings to produce a low magnetic density in a third magnetic circuit of said core, said third magnetic circuit using parts of said first two magnetic circuits, whereby a low core loss and very high light load efficiency is obtained, and additional means for switching said windings to produce flux in the respective magnetic circuits.

In testimony, that I claim the invention set forth above I have hereunto set my hand this 16th day of November 1932.

FRAZER W. GAY. 

